GM Service Manual Online
For 1990-2009 cars only

The Engine Scan Tool Data List contains all engine related parameters that are available on the scan tool. The list is arranged in alphabetical order. A parameter may appear in any one of the data lists, and in some cases may appear more than once, or in more than one data list in order to group certain related parameters together.

Use the Engine Scan Tool Data List only after the following conditions are determined:

    •  The Diagnostic System Check-Engine Controls is completed.
    •  There are no DTCs.
    • The on-board diagnostics are functioning correctly.

Scan tool values from an engine that is operating correctly may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents the values that would be seen on a normal operating engine.

Important: Do not use a scan tool that displays faulty data. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool may result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service information for use in diagnosis. If all values are within the typical range described below, refer to Symptoms - Engine Controls for diagnosis.

The column labeled Data List indicates where a parameter is located on the scan tool. Review the scan tool operating manual for the exact locations of the data lists. The following is a description of each term listed:

All: The Parameter is in all data lists indicated below.

Eng 1: Engine Data 1

Eng 2: Engine Data 2

EVAP: EVAP Data

FT: Fuel Trim Data

HO2S: HO2S Data

MF: Misfire Data

TAC: TAC Data

CMP: CMP Actuator Data

ODM: ODM Data

CH: Cooling/HVAC Data

CT: Cruise/Traction Data

ET: Electrical/Theft Data

IPC: IPC Data

FF: Freeze Frame Data

FR: Failure Records Data

Scan Tool Data List

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

Engine Idling/Radiator Hose Hot/Park or Neutral/Closed Loop/Accessories Off

A/C Disengage 1-8 History

CH

Reason for A/C Disengagement

Varies

A/C High Side Pressure Sensor

CH

0-5 Volts

Varies

A/C OFF for WOT

CH

Yes/No

No

A/C Pressure Disable

CH

Yes/No

No

A/C Relay Circuit Status

ODM

OK/Fault/Indeterminate

OK

A/C Relay Command

Eng 1, 2, MF, CH

On/Off

Off

A/C Request Signal

CH

Yes/No

No

APP Indicated Angle

Eng 1, 2, CMP, CT, EVAP, HO2S, FT, TAC

0-100%

0%

APP Sensor 1

TAC

0.9-4.5 Volts

1 Volt

APP Sensor 2

TAC

0.45-2.25 Volts

0.5 Volt

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

BARO

Eng 1, 2, CMP, EVAP, HO2S, FT, MF, TAC

65-104 kPa (8-16 psi)

Varies with altitude

Brake Pedal Signal Status

CT, TAC

Valid/Invalid

Valid

Calculated ECT - Closed Loop Fuel Control

Eng 2

-39°C to +40°C (-38°F to +104°F)

40°C (104°F)

Calculated ECT - Thermostat Diagnosis

Eng 2

-39°C to +140°C (-38°F to +284°F)

89°C (192°F)

Catalytic Converter Protection Active

FT, MF

Yes/No

No

Crank Request Signal

ET

Yes/No

No

Cruise Control Active

CT, IPC

Yes/No

No

Cruise Disengage 1-8 History

CT

Reason

Varies

Cruise Inhibited

CT

Yes/No

No

Cruise Inhibit Reason

CT

Reason

Varies

Cruise On/Off Switch

CT

On/Off

Off

Cruise Resume/Accel. Switch

CT

On/Off

Off

Cruise Set/Coast Switch

CT

On/Off

Off

Current Gear

Eng 1, 2, MF, CT, ET, IPC

P/N/Reverse/1st-5th

P/N

Current Gear Signal

ET

Valid/Invalid

Valid

Cycles of Misfire Data

MF

0-200 counts

Varies

Cylinder 1-6 Injector Circuit Status

ODM

OK/Fault/Indeterminate

OK

Cylinder 1-6 Knock Retard

Eng 1

Degree

0 Degrees

Decel. Fuel Cutoff

Eng 2, FT, HO2S

Active/Inactive

Inactive

Desired Exh. CMP Bank 1 or 2

CMP

Degree

Varies

Desired HO2S Bank 1 or 2 Sensor 1

HO2S

Lambda

Varies

Desired Idle Speed

Eng 1, 2, EVAP, CMP, TAC

0-7,000 RPM

650 RPM

Desired Int. CMP Bank 1 or 2

CMP

Degrees

Varies

DTC Set This Ignition

Eng 1, CMP, EVAP, FT, HO2S, TAC

Yes/No

No

EC Ignition Relay Command

Eng 1, TAC, ET

On/Off

On

EC Ignition Relay Feedback Signal

Eng 1, TAC, ET

0-25.5 Volts

12-14.5 Volts

ECM Reset

Eng 1, EVAP, FT

Yes/No

No

ECT Sensor

Eng 1, 2, CMP, EVAP, HO2S, FF, FR, FT, MF, TAC, CH, IPC

-39°C to +140°C (-38°F to +284°F)

Varies

Engine Load

Eng 1, 2, CMP, EVAP, HO2S, FF, FR, FT, MF, TAC, CH

0-99%

0-5% - Idle

3-7% - 2500 RPM

Engine OFF EVAP Test Conditions Met

EVAP

Yes/No

Varies

Engine Off Time

EVAP

0:00:00 Seconds

Varies

Engine Oil Level Switch

CMP, IPC

OK/Low

OK

Engine Oil Pressure Sensor

IPC

OK, Low

OK

Engine Oil Pressure Sensor

MF, CMP, IPC

kPa/psi

Varies

Engine Run Time

Eng 1, 2, EVAP, FT, HO2S, MF, TAC, CMP, ODM, CH

0:00:00

Varies

Engine Speed

ALL

RPM

575-700 RPM

EVAP Purge Solenoid Circuit Status

ODM

OK/Fault/Indeterminate

OK

EVAP Purge Solenoid Command

Eng 1, EVAP, FT

0-100%

Varies

EVAP Vent Solenoid Circuit Status

ODM

OK/Fault/Indeterminate

OK

EVAP Vent Solenoid Command

Eng 1, EVAP, FT

Venting/Not Venting

Varies

Exh. CMP Angle Bank 1 or 2

CMP

Degrees

Varies

Exh. CMP Bank 1 or 2 Command

CMP

0-99%

Varies

Exh. CMP Solenoid Bn. 1 or 2 Circuit Status

ODM

OK/Fault/Indeterminate

OK

Extended Travel Brake Pedal Switch

Eng 1, TAC, CT

Applied/Released

Released

FC Relay 1 Circuit Status

ODM

OK/Fault/Indeterminate

OK

FC Relay 1 Command

Eng 2, CH

ON/OFF

Varies

FC Relays 2 and 3 Command

Eng 2, CH

ON/OFF

Varies

FC Relays 2 and 3 Circuit Status

ODM

OK/Fault/Indeterminate

OK

Fuel Level Sensor Left Tank (Secondary)

EVAP, IPC

0-5 Volts

Varies

Fuel Level Sensor Right Tank (Primary)

EVAP, IPC

0-5 Volts

Varies

Fuel Pump Relay Circuit Status

ODM

OK/Fault/Indeterminate

OK

Fuel Pump Relay Command

Eng 1, 2

On/Off

On

Fuel Tank Level Remaining

Eng 1, EVAP, IPC, MF

Liter/Gallon

Varies

Fuel Tank Pressure Sensor

EVAP

in H2O/mm Hg

Varies

Fuel Tank Pressure Sensor

EVAP

0-5 Volts

Varies

Fuel Tank Rated Capacity

EVAP

Liter/Gallon

17.8 Gallons (67.3 Liters

Fuel Trim Learn

Eng 1, EVAP, FT, HO2S

Enabled/Disabled

Enabled

GEN L-Terminal Signal Command

ET

0-100%

Varies

Generator F-Terminal Signal

ET

0-100%

Varies

HO2S Bank 1 or 2 Sensor 1

Eng 1, EVAP, FT, HO2S

Lambda

1.0 Lambda

HO2S Bank 1 or 2 Sensor 2

Eng 1, FT, HO2S

0-1,006 mV

Varies 400-700 mV

HO2S Htr. Bn. 1 or 2 Sensor 1 or 2 Circuit Status

ODM

OK/Fault/Indeterminate

OK

HO2S Htr. Bn. 1 or 2 Sensor 1 Command

HO2S

0-99%

Varies

HO2S Sensing Element Bn. 1 or 2 Sensor 1

HO2S

Ohms

70-90 Ohms

Depends on Temperature

IAT Sensor

Eng 1, 2, EVAP, FT, HO2S, TAC, CMP, CH, FF, FR

-39° to +140°C (-38° to +284°F)

Varies

Ignition 0 Signal

Eng 1, 2 EVAP, TAC, ET, IPC

On/Off

On

Ignition 1 Signal

Eng 1, 2 EVAP, FT, MF, TAC, CMP, ET, IPC

On/Off

On

IMRC Solenoid Circuit Status

ODM

OK/Fault/Indeterminate

OK

IMRC Solenoid Command

Eng 1

On/Off

Off

Initial Brake Apply Signal

TAC, CT

Applied/Released

Released

Injector 1-6 Command

Eng 2, FT, MF

ms

Varies

Injector PWM Bank 1 or 2 Average

FT, MF

0-9 ms

4.6-5.4 ms

Int. CMP Angle Bank 1 or 2

CMP

Degrees

Varies

Int. CMP Bank 1 or 2 Command

CMP

0-99 %

Varies

Int. CMP Solenoid Bn. 1 or 2 Circuit Status

ODM

OK/Fault/Indeterminate

OK

Knock Retard

Eng 1, CH

Degrees

Varies

KS 1 or 2 Signal

Eng 1

Volts

Varies

Loop Status Bn 1 or 2 Sen. 1

Eng 1, 2, EVAP, FT, HO2S, FF, FR

Open Loop/Closed Loop

Closed Loop

Loop Status Bn 1 or 2 Sen. 2

Eng 1, 2, EVAP, FT, HO2S, FF, FR

Open Loop/Closed Loop

Open Loop

LT FT Bn. 1 or Bn. 2 Cruise/Accel.

Eng 1, 2, EVAP, FT, HO2S

-100 % to +100 %

0%

LT FT Bn. 1 or Bn. 2 Idle/Decel.

Eng 1, 2, EVAP, FT, HO2S

-100 % to +100 %

0%

MAF Sensor

Eng 1, 2, FT, HO2S, MF, TAC, CMP, FF, FR

0-655 g/s

3.4-6.3 g/s

MAF Sensor

Eng 2, EVAP, FT, HO2S, MF, TAC, CMP

0-5 Volts

0.9-1.7 Volts

MIL Circuit Status

ODM

OK/Fault/Indeterminate

OK

MIL Command

Eng 1, IPC

On/Off

Off

Mileage Since DTC Cleared

Eng 2

km - miles

Varies

Misfire Current Cyl. 1-6

MF

0-255 Counts

0

Misfire History Cyl. 1-6

MF

0-65,535 Counts

0

Moderate Brake Apply Signal

TAC, CT

Applied/Released

Released

PNP Switch

Eng 2, ET

Park/Neutral/In Gear

P/N

Power Enrichment

Eng 2, FT, HO2S, MF

Active/Inactive

Inactive

Reduced Engine Power

Eng 1, 2, TAC, IPC

Active/Inactive

Inactive

Short Term FT Bank 1 or Bank 2

Eng 1, 2, EVAP, FT, HO2S, FF, FR

-25 % to +25 %

-3% to +3%

Spark

Eng 1, 2, FT, HO2S, MF, CH, CT, FF, FR

-20 to +40 Degrees

2-10 Degrees

Starter Relay Circuit Status

ODM

OK/Fault/Indeterminate

OK

Starter Relay Command

ET

On/Off

Off

Start Up ECT

Eng 2, EVAP, FT, HO2S, CH

-39° to +140°C (-38° to +284°F)

Varies

Start Up IAT

Eng 2, EVAP, FT, HO2S, CH

-39° to +140°C (-38° to +284°F)

Varies

Stoplamp Pedal Switch

Eng 1, CT, TAC

Applied/Released

Released

System Power Mode

Eng 2, EVAP, TAC, ET

Off, Accessory, RAP, Run, or Crank Request

Run

TAC System Learned Counts

TAC

0-11 Counts

0

Torque Delivered Signal

FT, TAC, CT

0-100 %

Varies

Torque Request Signal

FT, TAC, CT

0-100 %

90-98 %

Total Fuel Trim Avg. Bank 1 or Bank 2

EVAP, FT, HO2S

-100 to +100 %

Varies

Total Misfire Count

MF

Counts

0

TP Desired Angle

Eng 1, 2, EVAP, TAC, CT

0-100%

Varies

TP Indicated Angle

Eng 1, 2, EVAP, FT, HO2S, MF, TAC, CMP, CT, FF, FR

0-100%

Varies

TP Sensor 1

TAC

0-5 Volts

0.5-0.8 Volts

TP Sensor 1 Learned Minimum

TAC

0-5 Volts

0-0.6 Volts

TP Sensor 2

TAC

0-5 Volts

4.7-4.1 Volts

TP Sensor 2 Learned Minimum

TAC

0-5 Volts

5-3.7 Volts

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

Traction Control Status

TAC, CT

Active/Inactive

Inactive

Transmission Gear Selector Signal

Eng 2

Valid/Invalid

Valid

TWC Temperature Calculated Bank 1 or Bank 2

FT, MF

316-1,095°C (600-2,000°F)

316-485°C (600-900°F)

Vehicle Security Status

Eng 2, ET, IPC

Password Learning, VTD Fail-Enable, Auto Learn Timer, Fuel Disable Until Ign Off, Fuel Disable Timeout, and Fuel Continue

Fuel Continued

Vehicle Speed Sensor

Eng 1, 2, EVAP, FT, HO2S, MF, TAC, CMP, CH, CT, IPC, FF, FR

Km/h

mph

Varies

Volumetric Efficiency

Eng 1, 2, EVAP, FT, HO2S, MF, TAC, CMP, CH

0-100 %

5-25 % - Idle and at 2500 RPM